question on CBQ

[ChengLin TAN <chenglin@acm.org>]

hi,

I created two nodes, and define the duplex link of CBQ type betw. nodes
n0 and n1.  Then i define two traffic class audioclass_ (priority 1) &
dataclass_(priority 2), and attach a cbr source at n0 and a ftp source
at n1.  i bind the cbr source as audioclass_ & ftp source as
dataclass_.   When i tried to run this test script, the following error
message appears :

ns test-cbqsimple.tcl
ns: _o21 unknown-flow 257 1 2 2:
    (_o21 cmd line 1)
    invoked from within
"_o21 cmd unknown-flow 257 1 2 2"
    invoked from within
"catch "$self cmd $args" ret"
    (procedure "_o21" line 2)
    (SplitObject unknown line 2)
    invoked from within
"_o21 unknown-flow 257 1 2 2"

Does anyone have any idea what can be wrong?  my test script is attached
below.  Thanks.

########### MY testscript ###########
set ns [new Simulator]
set n0 [$ns node]
set n1 [$ns node]

######################
# Link definition
######################
$ns duplex-link $n0 $n1 10Mb 2ms CBQ

################
# Layout in Nam
################
$ns duplex-link-op $n0 $n1 orient left

#####################################
# set cbr source
#####################################
set cbr0 [new Agent/CBR]
$ns attach-agent $n0 $cbr0

#set pkt-interval to 100ms, pkt size of 200 bytes
$cbr0 set interval_ 0.1
$cbr0 set packetSize_ 200
$cbr0 set fid_ 1

set cbrsink1 [new Agent/LossMonitor]
$ns attach-agent $n1 $cbrsink1
#####################################
# set tcp source
#####################################
set tcp0 [$ns create-connection TCP $n0 TCPSink $n1 2]

#set TCP window size and pkt size
$tcp0 set window_ 50
$tcp0 set packetSize_ 1024

set ftp0 [$tcp0 attach-source FTP]

####################
# queue class creation
####################
set qlim 20
set cbq_qtype_ DropTail

set topclass_ [new CBQClass]
$topclass_ setparams none 0 1.0 auto 8 2 0

### audio class
set audioclass_ [new CBQClass]
set q1 [new Queue/$cbq_qtype_]
$q1 set limit_ $qlim
$audioclass_ install-queue $q1
$audioclass_ setparams $topclass_ true 0.1 auto 1 1 0

### data class
set dataclass_ [new CBQClass]
set q2 [new Queue/$cbq_qtype_]
$q2 set limit_ $qlim
$dataclass_ install-queue $q2
$dataclass_ setparams $topclass_ true 0.9 auto 2 1 0

####
set cbqlink [$ns link $n0 $n1]

$cbqlink insert $topclass_
$cbqlink insert $audioclass_
$cbqlink insert $dataclass_

$cbqlink bind $audioclass_ 1

$cbqlink bind $dataclass_ 2

###################
# event definition
###################
$ns at 0.3 "$ftp0 start"
$ns at 10.0 "$ftp0 stop"

$cbr0 set dst_ [$cbrsink1 set addr_]
$ns at 0.0 "$cbr0 start"
$ns at 10.0 "$cbr0 stop"

$ns run